A machine of the type described initially is described, for example, in Italian Patent No. 1,204,029, only in respect of the unit for cutting the tube at the exit from the machine. In this known machine, the cutting members consist of circular cutters of low mass which, when the tube is to be cut, are brought up to the tube which advances and rotates about its own axis, and are put into axial and rotating movement by the contact with the tube itself. The circular cutters are in other words fitted so that they are free-running and idle on the corresponding supporting arms.
To obtain a more effective cut, particularly when the thickness of the tube is large, in certain cases electric motors associated with two circular cutters are used, these motors imparting the cutting motion to the cutters when they are required to cut the tube. This solution entails high costs and increases the masses present. Since the cutting unit on which the rotating cutting members are fitted has to move with a reciprocating motion along the direction of advance of the continuously produced tube, it is desirable to reduce to a minimum the masses present and consequently the inertial forces arising from the reciprocating traversing motion of the cutting unit.
The object of the present invention is to provide a machine of the type described initially, in which the cutting members are given a cutting motion for more effective cutting of the tube, with a simple, compact structure of limited mass to reduce the inertial forces present and also the costs of maintenance and production of the machine.